Process for dyeing a wool-acrylonitrile fiber mixture



United States Patent PROCESS FOR DYEING A WOOL-ACRYLONI'IRILE FIBER MIXTURE Lee Bidgood, Jr., Wilmington, Del., assignor to E. I. du Pont. de Nemours and Company, Wilmington, Del., a corporation of Delaware N0 Drawing. ApplicationAugust 28, 1952, Serial No. 306,935

Claims. (Cl. 8-21) The acrylonitrile polymers have been dyed only to weakshades or the Wool has been dyed with dyes that dye the polymerbut are not normally preferred for dyeing the wool in the blend. Exact shade matching with a standard' is a requirement of commercial dyeing.

It has been found that basic dyes have good afiinity for acrylonitrile polymers. These dyes provide extreme brilliance, good to excellent wet fastness and better light fastness than that provided with the same dyes ,on morda'nted cellulose. Since the number of dyes having affinity for acrylonitrile polymer "is very small, it isdesired to use these basic dyes. Unfortunately, these dyes, as'a class, stainor dye wool When conventional techniques are used, and these dyeshave ,notoriouslypoor fastness properties onwool. Hence, mixtures of polyacrylonitriles and Wool. dyed with basic dyes by conventional techniques are not commercially acceptable.

Anobject of this invention'is to provide a process for preferentially applying basic colorto the acrylonitrile' polymerin'the wool blends Without staining, the wool:

Another object is the provisionof a process for'dyein'g the'components in the blends, simultaneously or separate ly, tothe'sameor different shades. Other objects will ap-' pear hereinafter.

The'objectives'of this invention are reached by'apply-' ing'to acrylonitrile polymer/wool blendsa basic dye, that is, any'dye'commercially termed a-basic dye, in an'aqueous dye'bath containing'about 2.5 to'15% by'weightofan' aliphaticorganic acid andabout 0.1 to-about 2;0%" by. weight of an aliphatic non-ionic surfactant at about 160' to about 250 F., the weights being based onthe weight of the blend. The surfactant used may have detergent or dispersing properties in addition to its general wetting or surface-active 'charalcteristics. It has beenifound; as described in the copending. application of Hiller, Serial No. 306,936, that the basic dyes can'beapplie'd prefere'n;

tiall'y to polymers of acrylonitrile in blends containing, other components, suchas Wool, cotton, polyamides and polyesters, if the dyeing is done at a pH of about 31010 about5.0; Very gooddyeing is obtained and the materials in the blend may be dyed, separately 'or simultaneously. Certain basic dyes, however, have such an 'affinityfojr wool that staining or dyeing of the Wool occurseven within the pH range of '3 to 5. Bythe present invention any basic dye may be applied without troublesome staining of the wool, and all dyeings with basic dyes are consider- Also, it is frequently desirable to dye 7 ice 2. ably improved since scouring'can' be eliminated. Exact shade matching becomes possible.

The invention is further described belowinexamples' given for illustrative, but not limitative, purposes. Per centages are by weight. The percentages of dyestufis represent Weight relationships of dyes to total fiber'weights,

and the dyes are in the usualcommercial form. The-*- yellow basic dye of Example -I and several subsequent examples is identified at page 37-11 of the indicated B. I. O. S; report as Astrazon- Yellow 3G with the following structural formula:

(C1102 ,i0 H' -o H Nn* 00113" 01 0H1 OCH.

EXAMPLE I A 5 0/ 5 0 wool/ polyacrylonitrile" fabric (staple blend; 5 g.) was dyed with" a mixture of 0.76% yellow basic dye of-BIOS Misc. Report #ZO-"(PB 31004), 0i48%'" green basic color of C. I. 662, and 0.96% greenacid color of C. I. 735, in a 200 m1. bath for -2.hours at the boil. The bath contained 0.5 g. of hydroxyacetic acid and 0.05 g. of a-commercialnon-ionic detergent, Emulphbr' O, which is a longchain alco-hol'polyglycol ether prepared according to U. '8. 1,970,578. A good"uni0n'match"was obtained. The brightgreen dyeing'had fadeometer light fastness of 10-20 hours.

Ornittingthe hydroxacetic acidcaused halt ormore of the'ba-siccolor to dye the-woolQwith weakened shade on the'polyacrylonitrile'an'd very'poor 'fastness of the'dyeing: to light and to rubbing.

Thefollowing aliphatic, non-ionic surfactants could housed in this and the following examples with. comparable resultsz Pluronic F-68, acondensate (M..W.= 7500) 'of ethylene oxide with 'a' propylene glycol/propyl ene oxideproduct; Carbowax 400, an ethylene oxide/ ethylene glycol reaction" product; and Tween 80, a polyoxyethylene derivative of sorbitan mono-'oleate.

EXAMPLE II Using the' sameprocedure described in Example I, a- 5g. piece of 50/50 wool/polyacrylonitrilestaple blend fabric'was cross-dyed incontrzistirigcolors. The followingidye'stufis were used Percent Yellow'basic-dye of Ex.-I' s 0.200 Green basic dye'ofC. 1. 662 0.072 Red basic dye of C. 1.677 a 0.040" Red acid dye of C. I. 31 1.000

By this procedure the polyacrylonitrile was dyed to a neutral gray shade and't'ne wool'was dyed to a red shade. Both shades were clear and bright indicating that no cross-staininghad occurred'in the dyeing.

EXAMPLE HI A 5 g. piece of 50/50 Wool/polyacrylonitrile staple blend fabric wasidyed in a'200 ml. bath as follows: the piece'was started in thebath containing .2 orv 3 dropsof a solution'of 0:5 g. of hydroxyacetic acid; in 10ml.- of H20 and 0.8% of the acid dye of C. If 304.. The dye'ingwas'started at F. and the temperature was raised' to 200" F. over a period of '30 minutes. Two: or three moredrop of h'ydroxyaceticacid solution. were addedat 200 Ffto" exhaust the acid. The bath Was. then cooled to The balance ofthe hydroxyacetic acid'was added. Then 0.05 g. of the dispersing agent of Example I, 0.72% of the green basic dye of C. I. 662,

0.72% of the yellow basic dye of Example I, and 0.56% of the red basic dye of C. I. 677 were added. The dye bath was raised to the boil in fifteen minutes, and dyeing was continued at the boil for two hours. After rinsing and scouring for 30 minutes at 120 F. with 1% of the above dispersing agent (on weight of fiber) in the bath, the piece was ironed dry. A medium navy union shade was obtained. Repetition of this experiment with omission of the dispersing agent gave a considerably weaker dyeing of the polyacrylonitrile with the result that the shade could not be matched.

EXAMPLE IV A 50/50 wool/polyacrylonitrile staple blend fabric (5 g.) was dyed as follows: the piece was entered into a 200 ml. bath containing 0.1 g. of acetic acid and 0.03 g. of the dispersing agent of Example I and 1.0% of the yellow basic dyestuff of Example I and 1.12% of the yellow acid dyestuff of C. I. 642. The temperature was raised slowly to the boil over a period of 20 minutes and dyeing was continued at the boil for two hours. After rinsing and scouring for 30 minutes at 120 F. in a scouring bath containing 1% of the dispersing agent of Ex ample I (on weight of fiber), and then rinsing and drying, a bright yellow union was obtained. This dyeing had 20 to 40 hours fadeometer light fastness and showed only a trace staining in a standard AATCC alkaline perspiration test and withstood a 120 F. wool mill washing test for 30 minutes.

EXAMPLE V A 5 g. 50/50 wool/polyacrylonitrile staple blend fabric piece was dyed as follows: the piece was entered into a 200 ml. bath at 160 F. containing 0.5 g. of

NazSOa H2O 0.01 g. of acetic .acid and 0.76% of the red acid dyestuff of C. I. 430. The temperature was raised to the boil over a period of 20 minutes, and dyeing was continued at the boil for 30 minutes with addition of 0.01 g. of acetic acid minutes from the end of this time to promote exhaustion of the acid color on wool. The bath was then discarded. The piece was rinsed and entered in a fresh 200 ml. bath at 110 F. containing 0.15 g. of formic acid, 0.05 g. of the dispersing agent of Example I, 0.84% of the yellow basic dyestuff of Example I and 0.4% of the red basic dyestufi of C. I. 677. The temperature was raised to the boil in minutes and dyeing was continued for two hours at the boil. The piece was then rinsed,

scoured minutes at 120 F. in a scouring bath containing 1% of the dispersing agent of Example 'I, rinsed and dried. A level bright carmine shade was obtained.

The above procedure was again followed exactly except that the acid color was omitted from the first bath. This gave a bright dyeing in which the polyacrylonitrile only was dyed. The wool remained white indicating that the basic colors had not stained the wool.

When the above procedure was repeated exactly except that the basic colors were omitted from the formula, the wool only was dyed and the polyacrylonitrile remained white.

These results proved that each color had dyed only the fiber for which it was intended.

EXAMPLE VI A 75 g. 50/50 wool/polyacrylonitrile staple blend piece was dyed in rope form in a small scale laboratory beck. The piece was entered in a 3 liter dyebath at 110 F. containing 8.8 g. of hydroxyacetic acid (technical grade), 1.5 g. of the dispersing agent of Example I, 0.54 g. of the green basic dyestuff of C. I. 662 and 0.115 g. of the red basic dyestuff of C. I. 677. The beck was run and the temperature was raised slowly to the boil over a period of 30 minutes and dyeing was continued at the boil for .30 minutes. Then the bath was cooled (with the beck running) to 180 F. and 1 g. of H2804 was added and the beck was run for 5 minutes. Then 0.63 g. of the orange premetallized acid dyestuff of Prototype 146 was added, and the temperature was raised to the boil in 15 minutes. Dyeing was continued at the boil for 1.5 hours. The pH of the dye bath was 2.7 at the end of the dyeing. The fabric was rinsed, scoured 30 minutes at 55 C. in a 3 liter bath containing 1.5 g. of the above dispersing agent, rinsed and pressed dry. A cross-dyeing resulted in which the polyacrylonitrile was dyed a medium blue shade and the wool was dyed an orange shade. Clarity of the shades indicated that each dye had colored only the fiber for which it was intended. Repetition of this experiment using 9.8 g. of sulfuric acid instead of 8.8 g. hydroxyacetic acid and 1.0 g. sulfuric acid gave a weaker dyeing of polyacrylonitrile and a dull brown shade on the wool, indicating that the basic dyes had stained the wool.

EXAMPLE VII A 5 g. piece of 50/50 wool/polyacrylonitrile was dyed as follows: a piece was started in a 200 ml. bath at F. containing 0.5 g. of NazSOr- 101-120, 0.05 g. of the dispersing agent of Example I, 0.02 g. of acetic acid and 0.032 g. of the blue acid dye-stuff of Prototype 223. The temperature was raised to the boil over a period of 20 minutes. Dyeing was continued at the boil for 35 min utes. Then 0.05 g. of acetic acid was added to exhaust the color and dyeing was continued for 25 minutes at the boil. The bath was then discarded and the piece was rinsed and entered into a fresh 200 ml. bath at 110 F. containing 0.5 g. of tartaric acid, 0.05 g. of the above dispersing agent, and 0.030 g. of the blue basic dyestuif of C. I. 663. The temperature was raised to the boil over a period of 20 minutes and dyeing was continued at the boil for two hours. After the usual rinsing, scouring and drying, brilliant greenish blue union was obtained.

EXAMPLE VIII A 5 g. 50/50 Wool/polyacrylonitrile piece was entered in a 200 ml. dyebath at 110 F. containing 0.5 g. NazSOr-IOHzO, 0.05 g. of acetic acid and 0.025 g. of the brown mordant acid dyestufI of Pr. 14. The temperature was raised to the boil over a period of 20 minutes and dyeing was continued at the boil for 40 minutes. Then 0.05 g. of acetic acid was added to exhaust the color and dyeing was continued at the boil for 20 minutes. The bath was cooled to F. and 0.02 g. of sodium dichromate was added. The temperature was again raised to the boil over a period of 20 minutes and the chroming was continued at the boil for 0.5 hour. This bath was discarded. The piece was rinsed and then was entered in a fresh 200 ml. dyebath at 110 F. containing 0.05 g. of the dispersing agent of Example I, 0.75 g. of acetic acid, 0.05 g. of the yellow basic dyestufl of Example I, 0.004 g. of the red basic dyestuff of C. I. 677 and 0.004 g. of the green basic dyestuff of C. I. 662. The temperature was raised to the boil over a period of 20 minutes and dyeing was continued for a period of 2 hours at the boil. After the usual rinsing, scouring and drying, a brown union shade was obtained which was fast to 2 hours washing at 120 F.

EXAMPLE IX A 50 g. 50/50 wool/polyacrylonitrile staple blend piece was dyed in a small scale laboratory beck as follows: the piece was entered in a 2 liter bath 110 F. containing 0.3 g. of the dispersing agent of Example I, 0.4 g. of hydroxyacetic acid and 0.44 g. of the acid dyestuif which is a 2:1 mixture of the blue acid dye of C. I. 1076 and the green acid dye of C. I. 737. The temperature was raised to F. over a period of 20 minutes, then 0.22 g. of the green basic dyestuif of C. I. 662 and 0.19 g. of violet basic dye of C. I. 681 (dissolved in 1 ml. of acetone and 1 ml. of acetic acid) were added. The temperature was raised to the boil over a period of 30 minutes and dyeing was continued at theboilfor 2 hours. ,After the usualrinsi lgs SCOuring-and-drying apmedium blue union was obtained which had 10-20 hours. fadeometer fastness.

EXAMPLE X A 5 g. 50/50 wool/polyacrylonitrile piece was dyed according to the method described in" Example Only the dyestufi formulation waslchanged. Thepiece was started in 0.4% ofthe green basic' dyestuff of C. I. 662 and 0.12% of the red basicdyestuif-of-C. 1.677. For the wool 0.88% of the blue premetallizedacid-dyestufi-of Prototype No. 318 was used. Afterthe-usual rinsing, scouring and drying at medium blue-union was obtained. This dyeing had-20-40 hours fadeometer fastness and excellent fastness to alkaline perspiration (standard AATCC test) and 120 washing.

This example was repeated with lbs. of-fabric in commercial equipment. Essentially thesameresults were obtained.

EXAMPLES XI XVI In each of the following examples,(tab1e) theindicated weights of wool and-polyacrylonitrile fabrics were dyed together ,in a 200 ml. bath containing 0.5 g. hydroxyacetic acid and 0.05 g. of the dispersing agent of Example I and the indicated weights of dyestuii, The textilepieces were in each case placed in the bath at 110 F., .and the temperature raised slowly to the boil and dyeing continued at the boil for two hours:

After rinsing and scouring min. at.11-0.F.'in:;bath containing 1% dispersing agent of Example I (on fiber weight), rinsing and drying, it was noted that all of the above fabrics were dyed to essentially the same kelly green shade. This proved that results in this method are independent of percent of wool and polyacrylonitrile.

EXAMPLE XVII A 2.5 g. piece of 50/50 wool/polyacrylonitrile (staple blend) was dyed with a mixture of 0.76% of the yellow dye of Example I, 0.48% of the green basic color of C. I. 662, and 0.96% of the green acid color of C. I. 735 in a 100 ml. bath containing 0.5 g. hydroxyacetic acid and 0.05 of the dispersing agent of Example I The cloth and dyebath were entered cold in a pressure vessel, the temperature was raised slowly to 250 F. in minutes and held at 250 F. for 15 minutes. After rinsing and a 15 minute scour at 110 F. in 1% of the above dispersing agent, a bright kelly green union was obtained.

EXAMPLE XVIII Using exactly the same dyebath formulation as in Example XVII, except that 0.60% of green acid color of C. I. 735 was used instead of 0.96%, a 2.5 g. piece of 50/ 50 wool/polyacrylonitrile (stock blend) was dyed 4 hours at 155l65 F. After rinsing and scouring 15 minutes at 110 F. in 1% the dispersing agent of Example I, a kelly green union was obtained only slightly weaker in shade than that of Examples I and XVII.

EXAMPLE XIX A 2.5 g. piece of wool fabric and 2.5 g. of staple yarn composed of a copolymer of acrylonitrile and vinyl chloride (40:60) was dyed with a mixture of the basic yellow .dyes. .show a number of copolymers of acrylonitrile which may be used inthe process ofthisinvention.

dye of Example I (0.76%.),thegreenbasic color of VC. I. 662 (0.48%.) and-the green acid color of C. I. 735 (0.40%) in a 200 ml. aqueous bath for 2 hrs. atthe boil. Thebath also contained 0.5 g. of hydroxyacetic acid'and 0.05 g. of the non-ionic detergent of Example I. A satisfactory shade ,matchwas. obtained on the twotypes of fiber.

Thefibers of acrylonitrile polymers used in this invention can be prepared in many ways, for example, as shown in U. S. Patent 2,436,926. The fibers may be in the form of continuous filaments, yarn, staple or fabric. The polymers include polyacrylonitrile-(i. e., the homopolyrner) and copolymers whereinthe acrylonitrile component constitutes about 40% or more of'the polymer molecule. These copolymers can be prepared in many ways using with acrylonitrile such copolymerizable monomers asvinyl chloride, methylvinyl-ketone, styrene, butadiene,..vinyl pyridines,ve. g., the 94/ 16. copolymer of acrylonitrileand 2-vinylpyridine,acrylic, acid, methacrylic acid andthe like. Ofconsiderablecommercial interest are thepolymers containing at least acrylonitrile and these can be dyed satisfactojrilyby the process of this invention, for these polymers have affinity for the basic The U. S. Patents No. 2,491,471 and 2,436,926

Theblends contain about 5 to 95.% Wool. The acrylonitrilepolymer component and-the wool may be blended inany. way, and other materials ,,such as plasticizers. and

modifiers, may: be present.

Thealiphatic. organicacids are used in amounts. of

about 2.5 to about 15% .by weightof the material being dyed. In some cases;a's little= as 2% or less of the acid is needed. The aliphatic acids may be any ofthe-rnany vwater-soluble. acids, .such as. acetic, propionic, citric,.hy-

droxyacetic, formic,. tar taric, .maleic, fumaric, .succinic,

levelness and penetration of the dye on the acrylonitrile polymer. Mixtures ofthese-acids can be used and, if

desired, small amounts of mineral acids can be used with the organic acid. ,Amounts. of aliphatic organic acid less :than. 2.5% are generally. not preferred, because staining of the-wool occurs.

Amounts greater .than 15% .are generally avoided since at those levels the;.dye's.- are kept off both fibers.

The surfactants are non-ionic, long chain alcohol polyglycol ethers. They are prepared by the condensation of the alcohol with ethylene oxide or ethylene glycol. Any of the aliphatic surfactants shown in U. S. Patent No. 1,970,578 may be used in this invention. These surfactants are prepared by the reaction of ethylene oxide or ethylene glycol on the aliphatic alcohols given in the patent or such alcohols as sorbitol and mannitol. The surfactants are polyoxyalkylene derivatives of the alcohols. These surfactants can vary considerably in molecular weight depending upon the number of alkyleneoxy groups introduced. However, the surfactant must be non-ionic for ionic surfactants do not give the desired reservation. Further, they must be aliphatic, for non ionic, aromatic surfactants are not operable in the process of this invention. The surfactants are used in the amounts of about 0.1 to about 2.0% by weight of the blend being dyed. Smaller amounts do not reserve the wool as well as desired and do not increase the depth of shade on the acrylonitrile polymer. Larger amounts retard the dyeing of the acrylonitrile polymer.

While dyeing is achieved at slightly elevated temperatures, it is preferred to heat the dye bath in order to get dying rates which are commercially feasible. Temperatures below about F. are, therefore, not normally used and temperatures above 160 F. are applied. Temperatures above 250 F. can be used, those above 212 F. requiring pressure equipment. Such equipment is available in the dyeing industry and this invention does not require special equipment. The processes of this invention can be carried out conveniently in standard mill equipment and operations.

This invention provides commercially acceptable processes for dyeing mixtures of wood and polyacrylonitriles. In the presence of the non-ionic surfactants, the acids used do not retard the dyeing of the polyacrylonitriles, even in the high part of the acid concentration range. The basic colors are preferentially applied to the fibers of the crylonitrile polymer; the wool is not stained by any of the basic dyes. The dyer can readily obtain cross-dyed effects on wool/acrylonitrile unions. The amount of dye used may be varied to give tints or heavy shades as desired. Commercially acceptable union matching is obtained, for the dye used on the acrylonitrile polymer does not throw the final wool dyeing otf shade. Polyacrylonitrile has been very diflicult to dye and steps have been taken to modify the homopolymer to enhance its dyeability. Such modifications are unnecessary here, for the polyacrylonitrile can be dyed as it is obtained in its commercial form. The selective dyeing makes available dyed wool/acrylonitrile polymer blends for suiting material, other flat fabrics and the like.

Further, the dyeing process of this invention can be applied very successfully to the acrylonitrile polymers having high acrylonitrile content. Since these have been the most difficult to dye and since these polymers are of considerable commercial interest, the process of this invention facilities the marketing of shaped articles from these polymers. Also, essentially no staining occurs in the process of this invention and with the elimination of scouring superior shade matching is obtained and a more economical process is available to the trade.

I claim:

1. A process for selectively dyeing an acrylonitrile polymer in which the acrylonitrile component constitutes at least 40% of the polymer molecule in a mixture with wool which comprises treating the said mixture with an aqueous dye bath containing a basic dye, about 2.5% to about 15.0% of a water-soluble aliphatic carboxy acid and about 0.1% to about 2.0% of an aliphatic, non-ionic surfactant derived from ethylene oxide, said percentages being based on the weight of said mixture.

2. A process in accordance with claim 1 wherein said dye bath. is heated to a temperature of about 160 F. to about 250 F.

3. A process in accordance with claim 1 wherein said mixture contains about 5% to about Wool.

4. A process in accordance with claim 1 wherein said surfactant is a polyoxyalkylene derivative of an alcohol.

5. A process in accordance with claim 1 wherein said acid is acetic acid.

6. A process in accordance with claim 1 wherein said acid is hydroxyacetic acid.

7. A process for dyeing a wool/acrylonitrile polymer mixture of fibrous material, said polymer including at least 40% acrylonitrile component in the polymer molecule, which comprises selectively dyeing said polymer by subjecting the said mixture to the action of an aqueous dye bath containing a basic dye, about 2.5% to about 15.0% of a water-soluble aliphaticcarboxy acid, based on the weight of the said mixture, and about 0.1% to about 2.0%, based on the weight of the said mixture, of a non-ionic surfactant comprising a polyoxyalkylene derivative of a long-chain aliphatic alcohol; and dyeing said Wool with an acid dye.

8. A process in accordance with claim 7 wherein said wool in said mixture is dyed prior to said polymer.

9. A process in accordance with claim 7 wherein said polymer in said mixture is dyed prior to said wool.

10. A process for dyeing selectively the components of a Wool/acrylonitrile polymer mixture of fibrous material, said polymer including at least 40% acrylonitrile component in the polymer molecule, which comprises dyeing the wool with an acid dye and dyeing the said polymer with a basic dye by treating the said mixture with an aqueous dye bath containing compatible acid and basic dyes, about 2.5 to about 15.0% of a watersoluble aliphatic carboxy acid, and about 0.1% to about 2.0% of an aliphatic, alcohol polyglycol ether surfactant, said percentages being based on the weight of said mixture.

References Cited in the file of this patent Dyeing With Coal Tar Dyestuffs, by Whittaker and Wilcock, 5th ed., 1949, London; Balliere, Tindall and Cox publisher, p. 165.

Amer. Dyes, Reporter for December 12, 1949, pages P925-P928 incl. 

1. A PROCESS FOR SELECTIVELY DYEING AN ACRYLONITRILE POLYMER IN WHICH THE ACRYLONITRILE COMPONENT CONSTITUTES AT LEAST 40% OF THE POLYMER MOLECULE IN A MIXTURE WITH WOOL WHICH COMPRISES TREATING THE SAID MIXTURE WITH AN AQUEOUS DYE BATH CONTAINING A BASIC DYE, ABOUT 2.5% TO ABOUT 15.0% OF A WATER-SOLUBLE ALIPHATIC CARBOXY ACID AND ABOUT 0.1% TO ABOUT 2.0% OF AN ALIPHATIC, NON-IONIC SURFACTANT DERIVED FROM ETHYLENE OXIDE, SAID PERCENTAGES BEING BASED ON THE WEIGHT OF SAID MIXTURE. 